XML 107 R83.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Retirement Plans SERP (Details) - Supplemental Employee Retirement Plans, Defined Benefit - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Annual Benefit Amount | $ 50,000 |  |
Year of Benefit | 20 years |  |
Defined Benefit Plan, Other Information-Number of Employees Covered | 2 |  |
Defined Benefit Plan, Other Cost (Credit) | $ 36,000 | $ 40,000 | $ 43,000
Liability, Defined Benefit Plan | $ 533,000 | $ 597,000 |

X
- Definition Amount of Annual Benefit to be paid + References No definition available. + Details
Name: | fmbh_AnnualBenefitAmount
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of years benefit will be paid after retirement. + References No definition available. + Details
Name: | fmbh_YearofBenefit
Namespace Prefix: | fmbh_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of defined benefit plan cost (credit), classified as other. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanOtherCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of defined benefit pension and other postretirement plans. Includes, but is not limited to, employee group covered, type of benefit formula, type of benefits, cost sharing arrangement, funding policy, type of assets held, significant nonbenefit liabilities and information pertaining to multiple employer plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921 + Details
Name: | us-gaap_DefinedBenefitPlansGeneralInformation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(15)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109237824&loc=d3e1703-114919 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(15)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 + Details
Name: | us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |